This work entails study of the interaction between adrenal and gonadal steroids and the plasma proteins to which they bind. Specifically, the major effort involves the characterization of the interaction between these steroids and testosterone-estradiol-binding globulin and corticosteroid-binding globulin. We are at present involved in characterization of the proteins, possible role of the proteins in hormone action, and the effect of binding on egress of hormones from plasma. BIBLIOGRAPHIC REFERENCES: Rosner, W. and Smith, R.N. Isolation and Characterization of the Testosterone-Estradiol Binding Globulin from Human Plasma: Use of a Novel Affinity Column Biochemistry 14: 4813-4820, 1975. Rosner, W. The Binding of Steroid Hormones in Human Serum In: Trace Components of Plasma: Isolation and Clinical Significance, G.A. Jamieson and T.J. Greenwalt (eds.), Alan R. Liss, Inc., 1976, Vol. V, pp. 377-395.